Pump impeller

ABSTRACT

An impeller, which is rotatable about an axis, includes an inlet shroud and a backing plate. An inlet orifice is defined by the inlet shroud, and a plurality of outlet orifices are radially outward of the inlet orifice. A plurality of vanes are disposed between the inlet shroud and the backing plate. The vanes are formed integrally as one-piece with the inlet shroud.

TECHNICAL FIELD

This disclosure relates to impellers for fluid pumps.

BACKGROUND

Automobiles and other vehicles use pumps to pressurize fluids, increasethe speed of fluids, or both.

SUMMARY

An impeller is provided, and is rotatable about an axis. The impellerincludes an inlet shroud and a backing plate. An inlet orifice isdefined by the inlet shroud, and a plurality of outlet orifices arelocated radially outward of the inlet orifice.

The impeller also includes a plurality of vanes, which are disposedbetween the inlet shroud and the backing plate. The plurality of vanesare formed integrally as one-piece with the inlet shroud.

The above features and advantages, and other features and advantages, ofthe present invention are readily apparent from the following detaileddescription of some of the best modes and other embodiments for carryingout the invention, which is defined solely by the appended claims, whentaken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, isometric view of an impeller, viewed from aninlet side;

FIG. 2 is a schematic, exploded, isometric view of the impeller of FIG.1, viewed from a back side;

FIG. 3 is a schematic, isometric view of the assembled impeller of FIGS.1 and 2, viewed from the back side;

FIG. 4 is a schematic, exploded, isometric view of an alternativeimpeller, viewed from a back side;

FIG. 5 is a schematic, isometric view of the assembled impeller of FIG.4; and

FIG. 6 is a schematic graph illustrating operational results of theimpeller shown in FIGS. 1-3 compared with a different impeller.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numbers correspond tolike or similar components wherever possible throughout the severalfigures, there is shown in FIG. 1 an impeller 10. A pump (not shown),such as a centrifugal pump, may use the impeller 10 to increase thepressure and flow of a working fluid (not shown).

While the present invention may be described with respect to automotiveapplications, those skilled in the art will recognize the broaderapplicability of the invention. Those having ordinary skill in the artwill recognize that terms such as “above,” “below,” “upward,”“downward,” et cetera, are used descriptively of the figures, and do notrepresent limitations on the scope of the invention, as defined by theappended claims. Any numerical designations, such as “first” or “second”are illustrative only and are not intended to limit the scope of theinvention in any way.

The impeller 10 is operatively attached to a driveshaft 12 and rotatableabout an axis 14. As the driveshaft 12 rotates the impeller 10, theworking fluid is pumped by accelerating the working fluid outward fromthe axis 14. The path of the working fluid is illustrated in FIG. 1 byinlet flow 16 and outlet flow 18. The kinetic energy of the impeller 10is converted into pressure as outward movement of the working fluid isconfined by a pump casing (not shown) radially outward of the impeller10. In the view shown in FIG. 1, the impeller 10 generally operateswhile rotating in the counterclockwise direction.

The impeller 10 includes an inlet shroud 20 and a backing plate 22. Aplurality of vanes 24 are disposed between the inlet shroud 20 and thebacking plate 22. These vanes 24 transfer motion of the impeller 10 intomotion or pressure within the working fluid. The vanes 24 are formedintegrally as one-piece with the inlet shroud 20, such that the vanes 24are not separately or subsequently attached to the inlet shroud 20.

The inlet flow 16 enters an inlet orifice 26 defined by the inlet shroud20. The inlet orifice 26 is substantially co-axial with the driveshaft12 and the axis 14. The inlet flow 16 may be a substantially contiguousflow or stream of the working fluid. The outlet flow 18 exits through aplurality of outlet orifices 28, which are radially outward of the inletorifice 26 from the axis 14.

The impeller 10 may also be defined by a draft angle 30 formed on thevanes 24. The draft angle 30 opens from the inlet shroud 20 to thebacking plate 22. A first distance 31 between a base end 32, which isproximate to the inlet shroud 20, of the vanes 24 is smaller than asecond distance 33 between a plate end 34, which is distal to the inletshroud 20, of the vanes 24.

As the inlet flow 16 enters the impeller 10, the flow of working fluidis generally parallel with the axis 14. However, as the outlet flow 18exits the impeller 10, the flow of working fluid is generallyperpendicular to the axis 14 (i.e., the flow is radial). This change indirection may be referred to as “turning” the working fluid. Because ofthe draft angle 30, the first distance 31 between the vanes 24 issmaller than the second distance 33. Therefore, as the working fluidturns, it is moving toward the second distance 33 and is moving fromtighter space to freer space during the turn. Contrarily, if the draftangle 30 were reversed, the working fluid would be more constricted asit turns from axial flow to radial flow.

In the impeller 10 shown, the inlet shroud 20 and the vanes 24 may beformed as one-piece by a single-action mold. The single-action moldwould separate from the inlet shroud 20 and the vanes 24 substantiallyin the direction of the axis 14.

Referring also to FIG. 2 and FIG. 3, and with continued reference toFIG. 1, there is shown another view of the impeller 10. FIG. 2 shows anexploded isometric view of the impeller 10, shown from a back side,which is generally opposite of the view shown in FIG. 1. FIG. 3 showsthe impeller 10 in an assembled state from the same view as FIG. 2. Thedriveshaft 12 is removed from view in both FIG. 2 and FIG. 3.

The impeller 10 also includes a plurality of slots 36 formed in thebacking plate 22. A plurality of tabs 38 are formed on the plate end 34of the vanes 24. The tabs 38 are configured to mate with the slots 36.Therefore, the backing plate 22 and the vanes 24 are mated together,which may assist in carrying loads between the two components. The tabs38 and the slots 36 may mate through a slip fit, an interference fit(such as by snapping into the slots 36), or by a deformation fit.

Referring now to FIG. 4 and FIG. 5, and with continued reference toFIGS. 1-3, there is shown an alternative impeller 110. FIG. 4 shows anexploded isometric view of the impeller 110, from a back side viewpoint.FIG. 5 shows an isometric view of the assembled impeller 110. Inoperation, the impeller 110 and the impeller 10 shown in FIGS. 1-3 mayoperate in substantially identical fashion.

The impeller 110 includes an inlet shroud 120 and a backing plate 122. Aplurality of vanes 124 are disposed between the inlet shroud 120 and thebacking plate 122. These vanes 124 transfer motion of the impeller 110into motion or pressure within the working fluid. The vanes 124 areformed integrally as one-piece with the inlet shroud 120, such that thevanes 124 are not separately or subsequently attached to the inletshroud 120.

Inlet flow of the working fluid enters an inlet orifice 126 defined bythe inlet shroud 120. Outlet flow of the working fluid exits through aplurality of outlet orifices 128, which are radially outward of theinlet orifice 126.

The impeller 110 may also be defined by a draft angle formed on thevanes 124. The draft angle opens from the inlet shroud 120 to thebacking plate 122, such that a base end 132 of the vanes 124 is widerthan a plate end 134 of the vanes 124. In the impeller 110 shown, theinlet shroud 120 and the vanes 124 may be formed as one-piece by asingle-action mold.

The impeller 110 also includes a plurality of slots 136 formed in thebacking plate 122. A plurality of tabs 138 are formed on the end of thevanes 124, and are configured to mate with the slots 136.

In addition to mating the tabs 138 with the slots 136, the impeller 110further includes an annular ring 140 formed on the opposing side of thebacking plate 122 from the vanes 124. The annual ring 140 connects theplurality of tabs 138.

As shown in FIG. 4, a channel 142 may be formed in the backing plate122. The channel 142 may house the annular ring 140, such that theannular ring 140 is flush with the backing plate 122. However, theannular ring 140 may alternatively be formed on the backing plate 122without the channel 142.

In one illustrative manufacturing process for the impeller 110, afterthe inlet shroud 120 and the vanes 124 are formed as one-piece by thesingle-action mold, the tabs 138 are inserted into the slots 136 in thebacking plate 122. Then, the annular ring 140 is overmolded onto thebacking plate 122 and the plurality of tabs 138, such that formation ofthe annular ring 140 locks the tabs 138 to the backing plate 122.

Referring now to FIG. 6, and with continued reference to FIGS. 1-5,there is shown a schematic graph 200, which illustrates operationalresults of the impeller 10 shown in FIGS. 1-3 compared with a different,comparison impeller. The graph 200 shows the improved performance of theimpeller 10 over the comparison impeller.

The comparison impeller does not have the draft angle 30 shown in FIGS.1-3. The comparison impeller may have an opposite draft angle (openingfrom a backing plate toward an inlet shroud) or may be a foil impeller,which has vanes that are integral with, and bent outward from, thebacking plate. Therefore, as the working fluid turns from axial flow toradial flow in the comparison impeller, the fluid becomes moreconstricted. However, in the impeller 10, the first distance 31 issmaller than the second distance 33, such that the working fluid is lessconstricted as it turns from axial flow to radial flow.

Flow rate values 202 are shown on the left side, in liters per minute.Hydraulic efficiency 204, in percentage, is shown on the right side. Allvalues shown are illustrative, exemplary, and demonstrative, and thevalues are in no way limiting of the invention. To derive the data shownin the chart 200, the impeller 10 and the comparison impeller weresimulated as operating at the same speeds, approximately 8750revolutions per minute, and with the same working fluid, water-basedcoolant.

A bar 210 shows the flow rate of the impeller 10, and a bar 212 showsthe flow rate of the comparison impeller. As shown in the chart 200, theimpeller 10 yielded a higher flow rate over the comparison impeller.

A bar 214 shows the hydraulic efficiency of the impeller 10, and a bar216 shows the hydraulic efficiency of the comparison impeller. As shownin the chart 200, the impeller 10 had improved hydraulic efficiencyrelative to the comparison impeller.

The detailed description and the drawings or figures are supportive anddescriptive of the invention, but the scope of the invention is definedsolely by the claims. While some of the best modes and other embodimentsfor carrying out the claimed invention have been described in detail,various alternative designs and embodiments exist for practicing theinvention defined in the appended claims.

1. An impeller rotatable about an axis, comprising: an inlet shroud; abacking plate; an inlet orifice defined by the inlet shroud, and aplurality of outlet orifices radially outward of the inlet orifice; anda plurality of vanes disposed between the inlet shroud and the backingplate, wherein the plurality of vanes are formed integrally as one-piecewith the inlet shroud.
 2. The impeller of claim 1, further comprising: adraft angle formed on the plurality of vanes from the inlet shroud tothe backing plate, such that a first distance between a base end of theplurality of vanes is smaller than a second distance between a plate endof the plurality of vanes.
 3. The impeller of claim 2, furthercomprising: a plurality of slots formed in the backing plate; and aplurality of tabs formed on the plate end of the plurality of vanes,wherein the plurality of tabs are configured to mate with the pluralityof slots.
 4. The impeller of claim 3, wherein the inlet shroud and theplurality of vanes are formed as one-piece by a single-action mold. 5.The impeller of claim 4, further comprising: an annular ring formed onthe opposing side of the backing plate from the plurality of vanes andconnecting the plurality of tabs.
 6. The impeller of claim 5, whereinthe annular ring is formed by overmolding the annular ring onto thebacking plate and the plurality of tabs.
 7. An impeller rotatable aboutan axis, comprising: an inlet shroud; a backing plate; a driveshaftoperatively attached to the backing plate, and configured to impartkinetic energy to the backing plate; an inlet orifice defined by theinlet shroud, and a plurality of outlet orifices radially outward of theinlet orifice; a plurality of vanes disposed between the inlet shroudand the backing plate, wherein the plurality of vanes are formedintegrally as one-piece with the inlet shroud and the plurality ofvanes, inlet shroud, and backing plate define the plurality of outletorifices; a plurality of slots formed in the backing plate; and aplurality of tabs formed on a plate end of the plurality of vanes,wherein the plate end is adjacent the backing plate and the plurality oftabs are configured to mate with the plurality of slots.
 8. The impellerof claim 7, further comprising: a draft angle formed on the plurality ofvanes from the inlet shroud to the backing plate, such that a firstdistance between a base end of the plurality of vanes is smaller than asecond distance between the plate end of the plurality of vanes.
 9. Theimpeller of claim 8, wherein the inlet shroud and the plurality of vanesare formed as one-piece by a single-action mold.